// Copyright 2003-2005 Arthur van Hoff, Rick Blair
// Licensed under Apache License version 2.0
// Original license LGPL
package javax.jmdns.impl.tasks;

import java.io.IOException;
import java.util.Iterator;
import java.util.Timer;
import java.util.TimerTask;

import javax.jmdns.impl.DNSConstants;
import javax.jmdns.impl.DNSOutgoing;
import javax.jmdns.impl.DNSQuestion;
import javax.jmdns.impl.DNSRecord;
import javax.jmdns.impl.DNSState;
import javax.jmdns.impl.JmDNSImpl;
import javax.jmdns.impl.ServiceInfoImpl;

/** The ServiceResolver queries three times consecutively for services of a given
 * type, and then removes itself from the timer.
 * <p/>
 * The ServiceResolver will run only if JmDNS is in state ANNOUNCED. REMIND:
 * Prevent having multiple service resolvers for the same type in the timer
 * queue. */
public class ServiceResolver extends TimerTask {
	/**
     * 
     */
	private final JmDNSImpl jmDNSImpl;
	/** Counts the number of queries being sent. */
	int count = 0;
	private String type;

	public ServiceResolver(JmDNSImpl jmDNSImpl, String type) {
		this.jmDNSImpl = jmDNSImpl;
		this.type = type;
	}

	public void start(Timer timer) {
		timer.schedule(this, DNSConstants.QUERY_WAIT_INTERVAL,
				DNSConstants.QUERY_WAIT_INTERVAL);
	}

	@SuppressWarnings("rawtypes")
	public void run() {
		try {
			if (this.jmDNSImpl.getState() == DNSState.ANNOUNCED) {
				if (count++ < 3) {
					long now = System.currentTimeMillis();
					DNSOutgoing out = new DNSOutgoing(
							DNSConstants.FLAGS_QR_QUERY);
					out.addQuestion(new DNSQuestion(type,
							DNSConstants.TYPE_PTR, DNSConstants.CLASS_IN));
					for (Iterator s = this.jmDNSImpl.getServices().values()
							.iterator(); s.hasNext();) {
						final ServiceInfoImpl info = (ServiceInfoImpl) s.next();
						try {
							out.addAnswer(
									new DNSRecord.Pointer(info.getType(),
											DNSConstants.TYPE_PTR,
											DNSConstants.CLASS_IN,
											DNSConstants.DNS_TTL, info
													.getQualifiedName()), now);
						} catch (IOException ee) {
							break;
						}
					}
					this.jmDNSImpl.send(out);
				} else {
					// After three queries, we can quit.
					this.cancel();
				}
			} else {
				if (this.jmDNSImpl.getState() == DNSState.CANCELED) {
					this.cancel();
				}
			}
		} catch (Throwable e) {
			this.jmDNSImpl.recover();
		}
	}
}